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UNITED STATES PATENT OFFICE.

JAMES M. MCCULLOCH, OF GARSTONIENGLAND.

STEAM-BOILER.

SPECIFICATION forming part of Letters Patent No. 601,080, dated March 22, 1898.

v Application filed April 13,1897. Serial No. 632,041. (No model.)

To aZZ whom it may concern.-

Be it known that I, JAMES MCGOWAN Mo- OULLOOH, a subject of the Queen of Great Britain, residing at Garston, in the county of Lancaster, England, have invented certain new and useful Improvements in Steam-Boilers, of which the following is a specification.

This invention has for its object :a Watertube boiler which shall have thorough circulation, be easy to install and to repair, and at the same time be safe, economical, and get intoa small compass.

The invention will be understood from the following description, reference being had to the accompanying drawings, in which Figure 1 is a sectional elevation of a boiler constructed in accordance with my invention Fig. 2, a plan, partly in section; Fig. 3, an enlarged view showing one method of fastening the tube ends into the main water-chamber; Fig. 4, an end view of the tube ends fixed in the main water-chamber.

I form the main water tube or chamber of my boiler as a vertical cylinder A, with, if desirable, an enlarged dome B, of any desired shape, at the top. This vertical cylinderis by preference of sufficient diameter to allow a Workman to enter for cleaningor fitting, as required. All around the cylinder A, I place an outer casing-.0 at any required distance from the central tube A. This casing G'can be circular, oval, or other shape to suit the requirements. The space between the central tube A and the outer casing O is divided by a horizontal diaphragm D into two portions E and F.

Gis the fire-box or grate. Exactly opposite to the fire-box that' is, on the other side of the vertical tube A- I place a large hole H in the horizontal diaphragm D, and immediately above the fireplace I place an exit J through the roof of the casing.

In the vertical tube A,l form a large number of holes for tubes radiating outward. Tubes are placed through theseholes and radiate out from the vertical tube. The inner ends of these bent tubes, forming a U or rounded V, similar to the shape of a hair -pin, are screwed through the wall of the central tube and are supplied with nuts. Thus the nuts at both ends of the tube are protected from the furnace-gases. The U or rounded-V tubes are secured at both ends to the wall of the central tube, by preference in three series, one series above and, two below the diaphragm D. I prefer, as a rule, eight rows of holes in each set or series, in which case the first, second, third, and fourth rows, Fig.4, are arranged with the holes in different vertical planes alternating, the next four above, 5, 6, 7, and 8, in corresponding vertical planes with these four-that is, the holes in the highest plane are perpendicular above the holes in the fourth plane, the holes in the bottom plane with those in the fifth plane, &c. The tubes are placed through these holes,and, radiating out from the holes 1, 2, 3, and 4, Fig. 4, they return to the holes 5, 6, 7, and 8. This disposition of the tubes is clearly shown in the figures, the holes 1, 2, 3, and 4 being the ends of the bent tubes where they radiate out from the central tube A, and 5, 6, 7, and 8 the opposite ends of the same tubes where they return to the central tube, 1 and 5 being the same tube, 2 and 6 the same, and so on. By this arrangement the tubes project radially all around the central tube A directly inthe path of the flames and hot combustion-gases from the furnace, while the diaphragm D directs the course of hot gases from the furnace.

It will be obvious that there may be more than one diaphragm, and for different-sized boilers there'may be two, three, or even four series of tubes between each diaphragm, the gases from the furnace passing through each by holes on opposite sides to the holes in the diaphragms above and below. The bottom series of radial tubes extend only so far as the fire-bridge L, thus leaving a clear space for the grate. The ends of the bent watertubes are fastened in the wall of the chamber' A'by screwing the ends of the tubes and tapping the holes in the cylinder A to receive the screw-bushin g M. The curve of the tubeplate is taken ofi by a countersink-drill, and the screwed bushing M turned conical and screwed up to the countersink, making a permanent water-tight joint. Lock-nuts N are screwed onto the tube ends against the bushings M. Should a tube give out from any cause and sufficient time not be available to renew the same, (although only a short time is required to change a tube,) the lock-nuts N on both ends of the tube may be changed for screwed blind caps. The furnace G is formed with arched brickwork O, and the grate may be divided by a mid-feather, if necessary.

In action the course of the gases from the furnace is through and among the second and lower series of water-tubes K and all around the central water-chamber A, then through the opening II in the diaphragm D, returning to the frontin the upper series of water-tubes, where the uptake J and chimney are placed. The casing may be extended beyond the tube ends for the uptake J, so as to enlarge the same at the base of the funnel. The casing O is made in sections or segments, so as to be readily portable and easily put together. The central water-tube A ends some distance below the lowest series of radial water-tubes, so as to have a settling-place for sediment, and in this settling part I place a blow-oft cock.

In Fig. l I have only shown some of the holes in the central tube from which the smaller tubes radiate; but it must of course be understood that these holes go around the tube, as described.

The outer casing is closed at the top at a point below the top of cylinder A, so that the steam-space at the top of said cylinder A and in the dome B is entirely above the heatingspace within said casing and the danger of overheating is avoided. This arrangement of a central vertical water-cylinder with the grate entirely at one side of same has the advantage of affording a Very substantial support for the cylinder, the same resting, as shown, right on a solid foundation. By having the grate on one side only case in firing is obtained, and in order to produce at the same time a uniform heating effect I have caused the gases from the fire-box to be first deflected to the other side of the heatingspace by the diaphragm D and to then return to the side above the fire-box, so as to pass out by the exit. The stepped series or successively-ascending arrangement of the water-tubes K also tends to uniformity in the heating action, and more especially to better circulation both of the gases in the heatingspace and of the heated water.

I declare that what I claim is- A steam-boiler, comprisingin combination, an outer casing C closed at the top and having on one side an exit-pipe J, a central watercylinder A, surrounded by casing C, and extending above same, and having a steamcollecting receptacle or dome above the easing 0, a fire-box G on one side of the central cylinder A and communicating with the heating-space between the said cylinder and casing at a point below the exit-pipe J, a diaphragm D extending horizontally across this heating-space and having a hole on the side away from the fire-box, and bent water-tubes K arranged in stepped series, in the portions of the heating-space above and below the diaphragm D, substantially as set forth.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

.I. M. MCCULLOCII.

Vitnesses:

W. P. THOMPSON, W. II. BEESTON. 

